EP2877386B1 - Lane change assistance system for vehicle - Google Patents

Description

The present invention generally relates to a driving assistance system for a vehicle and more particularly to a lane-assisting system for a motor vehicle.

A system implementing the Lane Change Assist (LCA) function currently offered on a number of vehicles uses two radars located at the left rear and the right rear of the vehicle. vehicle behind the bumper. The radars make it possible to "see" on adjacent lanes up to 70 meters behind the vehicle, and to position the vehicles detected in the horizontal plane in X and Y.

1. (i) la fonction 'Surveillance Angle Mort' (SAM) qui prévient le conducteur de la présence d'un véhicule dans la zone angle mort dans le cas où le véhicule porteur du système se fait dépasser par un véhicule cible, et dans le cas où le véhicule porteur du système dépasse un véhicule cible avec un différentiel de vitesse inférieur à un certain seuil (typiquement 10km/h) ; et
2. (ii) la fonction 'avertissement d'un véhicule approchant' (en anglais, 'Closing Vehicle Warning' (CVW)) qui prévient le conducteur de la présence d'un véhicule dans une voie adjacente lorsque le temps avant collision (en anglais, 'Time To Collision' (TTC)) devient inférieur à un seuil à paramétrer (typiquement 4 secondes). Le temps avant collision (TTC) est défini comme le temps mis par le véhicule cible pour arriver au niveau du pare-choc arrière du véhicule porteur du système dans l'hypothèse où les vitesses de l'un et de l'autre demeureraient constantes. C'est donc la distance entre les deux véhicules que divise la vitesse relative entre les deux véhicules.

In addition, the system implements two sub-functions:

1. (i) the 'Dead Angle Surveillance' (SAM) function which warns the driver of the presence of a vehicle in the blind spot zone in the event that the vehicle carrying the system is overtaken by a target vehicle, and in the case of where the vehicle carrying the system exceeds a target vehicle with a speed differential below a certain threshold (typically 10km / h); and
2. (ii) the ' Closing Vehicle Warning ' (CVW) function which warns the driver of the presence of a vehicle in an adjacent lane when the collision time (in English, ' Time To Collision ' (TTC)) becomes lower than a threshold to set (typically 4 seconds). The pre-collision time (TTC) is defined as the time taken by the target vehicle to reach the rear bumper of the vehicle carrying the system in the event that the speeds of one and the other would remain constant. It is therefore the distance between the two vehicles that divides the relative speed between the two vehicles.

• En zone SAM, le radar doit couvrir en latéral, par rapport au flanc du véhicule, de 0 à une distance de l'ordre de 4 à 5 mètres, et en longitudinal, sur une zone comprise entre la ligne rétroviseur et jusqu'à une distance de l'ordre de 4 à 5 mètres derrière le pare-choc arrière ;
• En zone CVW, le radar doit couvrir en latéral, par rapport au flanc du véhicule, de 0 à une distance de l'ordre de 4 à 5 mètres, et en longitudinal, sur une zone comprise entre la fin de la zone SAM et jusqu'à environ 70 mètres derrière le pare-choc arrière du véhicule.

The radar coverage area needed in a straight line is typically the following (same left-right coverage areas):

• In the SAM zone, the radar shall cover, in the lateral direction, with respect to the sidewall of the vehicle, 0 at a distance of the order of 4 to 5 meters, and longitudinally over an area between the rear view mirror line and up to a distance of distance of about 4 to 5 meters behind the rear bumper;
• In the CVW zone, the radar shall cover, in lateral relation to the side of the vehicle, 0 at a distance of the order of 4 to 5 meters, and in the longitudinal direction, in an area between the end of the SAM zone and up to approximately 70 meters behind the vehicle's rear bumper.

For the CVW function, in order to be able to determine the position of the relevant target vehicles present in the adjacent lanes, it is necessary to estimate a "trajectory history" of the carrier vehicle of the system. This is usually achieved by using available vehicle data that is vehicle speed and yaw rate and / or steering wheel angle.

This trajectory history is placed in the reference of the carrier vehicle and adjacent "virtual" channels are then "placed" on either side of this trajectory history.

This works well in most cases, typically when the carrier vehicle remains in its lane. The Figure 1 illustrates the trajectory history 1 of the carrier vehicle 3. The target vehicle 5 and the most likely future trajectory 7 of the target vehicle 5 (if it remains in its lane) is also illustrated. Zones 9 are the areas considered to represent adjacent lanes and the dotted lines represent true discontinuous lines 11 of the infrastructure.

Since the carrier vehicle 3 has remained in its lane, the "estimated" adjacent lanes 9 correspond to the adjacent lanes of the infrastructure, and if the inter-vehicle time (TIV) is sufficiently low, the vehicle 5 will be signaled to the driver of the vehicle carrier 3, and this is relevant.

However, this can induce false detections or no detections in the case where the carrier vehicle of the system 3 changes lane. In this case, the trajectory history 1 is no longer relevant for a certain time before returning to it.

The Figure 2 illustrates the case where the carrier vehicle 3 of the system changes lanes, to go from the third lane V3 to the second lane V2. The vehicle 5 which is also on the second channel V2 is present on the estimated adjacent lane 9 by the system, which no longer corresponds to the adjacent lane. If the inter-vehicle time TIV is below the threshold, it will be reported to the driver of the carrier vehicle 3 as being in the left adjacent lane, when this is no longer the case. A target vehicle 13 that is on the third V3 lane (or the first lane), will only be reported late, even if its inter-vehicle time TIV would justify it before, because it has not yet returned the estimated adjacent lane 9, while it is on the true adjacent lane of the carrier vehicle 3.

This phenomenon will be easier to meet as the system operates at low vehicle speeds.

The document US6388565 discloses a lane-assisting system including means for determining the path taken by the vehicle, means for determining the geometry of the roadway, means for determining a position of a target vehicle, and means for signaling the presence of the target vehicle in an adjacent lane. However, this system does not allow the detection of vehicles in adjacent lanes after a lane change of the carrier vehicle of the lane departure assistance system.

The document DE10327869 describes a system according to the preamble of claim 1.

This system does not allow the detection of vehicles in adjacent lanes after a lane change of the carrier vehicle of the lane departure assistance system.

An object of the present invention is to meet the drawbacks mentioned above and in particular to propose a lane-assisting system which ensures the detection and the signaling of the presence of vehicles in the adjacent lanes after a change of direction. way of the vehicle carrying a lane change assistance system and thus limits false detections or no detections in the case where the carrier vehicle of the system changes lanes.

For this, a first aspect of the invention relates to a lane-assisting system for a vehicle according to the characterizing part of claim 1.

Such a system makes it possible to reconstruct the "true" lanes corresponding to the road lanes, to know in which lane of the road the carrier vehicle is located and to determine whether a target vehicle is in a "real" adjacent lane. Such a system ensures the detection of the presence of vehicles in the adjacent lanes even after a lane change of the carrier vehicle.

Advantageously, it further comprises means for determining, as a function of time, a position of the lane marking lines with respect to the vehicle.

Very advantageously, the means for determining a trajectory of each of the lane marking lines are configured to calculate a trajectory of each of the lane marking lines using the trajectory taken by the vehicle and the position of the lane marking lines. .

A particularly interesting embodiment is that it is configured to determine the track of a follower vehicle by using the trajectories of the lane marking lines and the position of the follower vehicle with respect to the vehicle, and to determine the lane of the vehicle by using the trajectories of the lane marking lines and the position of the vehicle.

Advantageously, the means for determining a position of the lane marking lines with respect to the vehicle comprise a camera positioned at the front of the vehicle and / or a camera positioned at the rear of the vehicle.

Advantageously, it comprises a satellite navigation and positioning system including a route lane mapping, the system being configured to determine a trajectory of the road lane marking lines from the lane mapping.

According to a second aspect, the present invention relates to a method for determining the presence of a follower vehicle in a lane adjacent to a lane of a vehicle according to the object of claim 7.

Advantageously, it further comprises the step of determining, as a function of time, a position of the lane marking lines with respect to the vehicle.

Advantageously, during the step of determining a trajectory of the lane marking lines, a trajectory of each of the lane marking lines is calculated using the trajectory taken by the vehicle and the position of the marking lines of the lanes. way.

According to a third aspect, the present invention relates to a motor vehicle comprising a system as defined above.

• la Figure 1 illustre l'historique de trajectoire d'un véhicule porteur et la trajectoire la plus probable d'un véhicule suiveur ;
• la Figure 2 illustre le cas où le véhicule porteur change de voie, pour passer de la troisième voie à la deuxième voie, et le véhicule suiveur se trouve sur la deuxième voie que le système conventionnel d'assistance au changement de voie signale toujours comme une voie adjacente ;
• la Figure 3 représente un système d'assistance au changement de voie selon un premier mode de réalisation de la présente invention ;
• La Figure 4 illustre une trajectoire (X(T), Y(T)) du véhicule porteur calculée par les moyens pour déterminer une trajectoire prise par le véhicule ;
• La Figure 5a illustre les positions des lignes de marquage de voie à un instant T déterminées par le système d'assistance au changement de voie de la présente invention ;
• La Figure 5b illustre les positionnements des lignes externes de marquage par rapport au véhicule porteur suivant l'axe y pour un temps T compris entre 0 et t déterminés par le système d'assistance au changement de voie de la présente invention;
• La Figure 5c illustre les trajectoires des lignes de marquage externes calculées par le système d'assistance au changement de voie de la présente invention pour T compris entre 0 et t ;
• La Figure 5d illustre la trajectoire (X_ligne(T),Y_ligne(T)) de chacune des lignes de marquage de voie dans le repère du véhicule porteur pour un temps T compris entre 0 et t calculée par les moyens pour déterminer une position des lignes de marquage de voie de la présente invention ;
• La Figure 6 illustre le cas où le véhicule porteur du système d'assistance au changement de voie selon la présente invention change de voie, pour passer de la troisième voie V3 à la deuxième voie V2 ;
• la Figure 7 représente un système d'assistance au changement de voie selon un deuxième mode de réalisation de la présente invention.

Other features and advantages of the present invention will appear more clearly on reading the following detailed description of an embodiment of the invention given by way of non-limiting example and illustrated by the appended drawings, in which:

• the Figure 1 illustrates the trajectory history of a carrier vehicle and the most likely trajectory of a follower vehicle;
• the Figure 2 illustrates the case where the carrier vehicle changes lanes, to move from the third lane to the second lane, and the follower vehicle is on the second lane that the conventional lane assist system still signals as an adjacent lane;
• the Figure 3 represents a lane-assist system according to a first embodiment of the present invention;
• The Figure 4 illustrates a trajectory (X (T), Y (T)) of the carrier vehicle calculated by the means for determining a trajectory taken by the vehicle;
• The Figure 5a illustrates the positions of the lane marking lines at a time T determined by the lane assist system of the present invention;
• The Figure 5b illustrates the positioning of the outer marking lines with respect to the carrier vehicle along the y-axis for a time T between 0 and t determined by the lane-assisting system of the present invention;
• The Figure 5c illustrates the trajectories of the external marking lines calculated by the lane assist system of the present invention for T between 0 and t;
• The Figure 5d illustrates the trajectory (X _line (T), Y _line (T)) of each of the lane marking lines in the reference of the carrier vehicle for a time T between 0 and t calculated by the means for determining a position of the lines of lane marking of the present invention;
• The Figure 6 illustrates the case where the carrier vehicle of the lane-assisting system according to the present invention changes lane, to pass from the third lane V3 to the second lane V2;
• the Figure 7 represents a lane assist system according to a second embodiment of the present invention.

The Figure 3 represents a lane-assist system according to a first embodiment of the present invention. The system 15 comprises means 17 for determining a trajectory taken by the vehicle 3, means 19 for determining a position of a follower vehicle 5 with respect to the vehicle 3, means 21 for determining, as a function of time, a position of the road marking lines on a road, means 23 for calculating a path of each of the lane marking lines and means 25 for signaling the presence of a follower vehicle 5. The system 15 further comprises a central computer 27.

The means 17 for determining a trajectory taken by the vehicle (the trajectory history of the carrier vehicle) comprises a computing unit 28 and storage means 29, such as a flash memory, including software for building or establishing a trajectory (X, Y) followed by the carrier vehicle 3 of the system 15 in the reference frame of the carrier vehicle 3 using vehicle odometer data 3, such as measured values of the speed V _x of the vehicle 3 and the yaw rate V vehicle _psi 3.

The vehicle speed V _x and the yaw rate V _psi are measured regularly (for example, they are provided by the ESP system (electro-stabilizer programmed) of the vehicle to correct the trajectory of the vehicle) and these measured values are provided to the calculation unit 28 to determine the trajectory taken by the vehicle 3.

The calculation unit 28 is configured to reconstitute, at time t, the trajectory (X, Y) of the carrier vehicle 3 in the reference of the carrier vehicle.

For each instant t, the trajectory (X, Y) includes a value X of a first x coordinate axis extending in a direction substantially along the length of the carrier vehicle, and a Y value of a second coordinate axis y. extending in a direction substantially along the width of the carrier vehicle, the second coordinate axis y being perpendicular to the first x coordinate axis.

From a time t = 0, the computing unit 28 records the information provided: longitudinal speed V _x (t) and yaw rate V _psi (t) of the carrier vehicle.

$$X_{\mathit{abs}}\left(t\right)=\underset{0}{\overset{t}{\int }}{V}_X\left(t\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)\mathrm{.}\mathit{dt}$$

$$Y_{\mathit{abs}}\left(t\right)=\underset{0}{\overset{t}{\int }}{V}_X\left(t\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)\mathrm{.}\mathit{dt}$$

où ψ(t) est l'angle de lacet et dψ(t)/dt la vitesse de lacet.The calculation unit 28 is configured to calculate at each instant t the trajectory of the carrier vehicle 3 in the absolute reference frame "Earth", according to the following equations: $$\psi \left(t\right)=\underset{0}{\overset{t}{\int }}\left(\frac{\mathit{d\psi }\left(t\right)}{\mathit{dt}}\right)\mathrm{.}\mathit{dt}$$

$$X_{\mathit{abs}}\left(t\right)=\underset{0}{\overset{t}{\int }}{V}_X\left(t\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)\mathrm{.}\mathit{dt}$$

$$Y_{\mathit{abs}}\left(t\right)=\underset{0}{\overset{t}{\int }}{V}_X\left(t\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)\mathrm{.}\mathit{dt}$$

where ψ (t) is the yaw angle and d ψ (t) / dt the yaw rate.

The X _abs (T) and Y _abs (T) values, for T between 0 and t, are stored in the storage means 29 to determine the trajectory taken by the vehicle 3.

$$Y\left(T\right)=\left(Y_{\mathit{abs}}\left(T\right)-Y_{\mathit{abs}}\left(t\right)\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)-\left(X_{\mathit{abs}}\left(T\right)-X_{\mathit{abs}}\left(t\right)\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)$$

et la Figure 4 illustre une trajectoire (X(T), Y(T)) du véhicule porteur 3 calculée par l'unité de calcul 28.The calculation unit 28 is configured to calculate, at each instant t, the trajectory X (T), Y (T) in the reference of the carrier vehicle, for T between 0 and t, according to the following equations: $$X\left(T\right)=\left(X_{\mathit{abs}}\left(T\right)-X_{\mathit{abs}}\left(t\right)\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)+\left(Y_{\mathit{abs}}\left(T\right)-Y_{\mathit{abs}}\left(t\right)\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)$$

$$Y\left(T\right)=\left(Y_{\mathit{abs}}\left(T\right)-Y_{\mathit{abs}}\left(t\right)\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)-\left(X_{\mathit{abs}}\left(T\right)-X_{\mathit{abs}}\left(t\right)\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)$$

and the Figure 4 illustrates a trajectory (X (T), Y (T)) of the carrier vehicle 3 calculated by the calculation unit 28.

The means 21 for determining a position of the lane marking lines on a road, at each instant t, are configured to position the lines corresponding to the marking of the tracks in the reference of the carrier vehicle 3.

The means 21 include a front camera CA1 and / or a rear camera CA2, a computer 31, storage means 33 (such as a flash memory) and software, for example, of the type used for the warning systems. Involuntary Line Crossing (AFIL). The software is stored in the storage means 33.

The computer 31 is able to receive the images of the front camera CA1 and / or the rear camera CA2 and to implement the software in order to process the images and to position the lane marking lines at each instant, with respect to the vehicle carrier, and for a time T between 0 and t, along the y axis.

For example, the positions of the lane marking lines at time T posY _line1 (T), posY _line2 (T), posY _line3 (T) and posY _Inline4 (T) determined by the computer 31 are illustrated in Figure 5a . The Figure 5b illustrates the positioning of the external marking lines with respect to the carrier vehicle along the y axis for a time T between 0 and t determined by the computer 31. The computer 31 determines the distance along the y axis between the carrier vehicle and each external marking line that the vehicle exceeds. This is in fact done for all lane marking lines that the carrier vehicle exceeds for a time T between 0 and t.

The means 23 for calculating a trajectory of each of the lane marking lines with respect to the vehicle include the computer 31 and the storage means 33 comprising an algorithm for calculating the trajectory of each of the ground marking lines in the reference frame of the carrier vehicle. 3, for a time T between 0 and t.

The computer 31 is connected to the computing unit 28 and able to receive the values of the trajectory (X (T), Y (T)) of the carrier vehicle calculated by the calculation unit 28.

The computer 31 is configured to implement the algorithm in order to calculate the trajectory of each of the lane marking lines in the reference of the carrier vehicle 3, for a time T between 0 and t.

$$Y_{\mathit{ligne}1}\left(T\right)=Y\left(T\right)+\mathit{pos}{Y}_{\mathit{ligne}1}\left(T\right)$$

où X(T) et Y(T) sont les valeurs de la trajectoire prise par le véhicule porteur calculées par l'unité de calcul 28.For example, according to the algorithm, the trajectory (X _line (T), Y _line (T)) of each of the lane marking lines is calculated according to the following equations, given here for the line No. 1 (L1 in the Figure 5c ): $$X_{\mathit{line}1}\left(T\right)=X\left(T\right)$$

$$Y_{\mathit{line}1}\left(T\right)=Y\left(T\right)+\mathit{pos}{Y}_{\mathit{line}1}\left(T\right)$$

where X (T) and Y (T) are the values of the trajectory taken by the carrier vehicle calculated by the calculation unit 28.

The Figure 5c illustrates the trajectories L1 and L4 of the external marking lines calculated by the computer 31 for T between 0 and t. The Figure 5d illustrates the trajectory (X _line (T), Y _line (T)) of each of the channel marking lines (L1 to L4) calculated by the computer 31 for T between 0 and t.

The means 19 for determining a position of a follower vehicle 5 with respect to the carrier vehicle 3 comprise a radar system 34 including two radars R1, R2 positioned at the rear left and rear right of the carrier vehicle 3 and a calculator Configured to receive the values calculated by the system 34 such as the longitudinal relative distance of the target vehicle 5 from the carrier vehicle 3, the relative angle of the target vehicle 5 with respect to the carrier vehicle 3 as well as the longitudinal relative velocity of the vehicles .

The radar system 34 is able to determine if one or more target vehicles are in the aforementioned 'Dead Angle Surveillance' (SAM) area and to provide a signal indicating the presence of a target vehicle in the SAM zone to the computer. The two radars R1, R2 of the radar system 34 furthermore cover the previously mentioned CVW zone on the left and right side of the carrier vehicle 3.

The computer 35 is further configured to position the target vehicle (s) at a _target position X (t), Y _target (t) in the carrier vehicle mark 3 using the measured values of the distance relative and the relative angle of the target vehicle 5 with respect to the carrier vehicle 3.

The central computer 27 of the system 15 is connected to the means 23 for calculating a trajectory of each of the lane marking lines, the means 19 for determining a position of a follower vehicle 5 with respect to the carrier vehicle 3 and the means 25 for signaling the presence of the following vehicle 5.

The central computer 27 includes storage means 37, such as a flash memory, comprising an algorithm for operating the system 15 and for identifying the target vehicle (s) needing to warn the driver of the carrier vehicle .

The central computer 27 is adapted to receive the _target position X (t), Y _target (t) of a follower vehicle 5 and the signal indicating the presence of a target vehicle in the SAM zone of the computer 35 as well as the values of the relative distance, the relative angle of a follower vehicle and the longitudinal relative speed. The central computer 27 determines that the follower vehicle 5 is not in the SAM zone when the signal indicating the presence of a follower vehicle in the SAM zone is not received and the central computer 27 receives the relative position X _target ( t), Y _target (t) of the computer 35,

In addition, the central computer 27 is adapted to receive the trajectory (X _line (T), Y _line (T)) of each of the lane marking lines of the computer 31. These data are stored in the storage means 37.

The central computer 27 is configured to implement the algorithm to identify the target vehicle (s) needing to warn the driver of the carrier vehicle.

The central computer 27, by implementing the algorithm, calculates a channel number i to be assigned to a target vehicle 5. For each target vehicle, the calculated trajectories (X _line (T), Y _line (T)) and the relative position of the vehicle target (X _target (t), Y _target (t)) are used to assign a channel number i to the target vehicle 5.

The central computer 27 first looks for the time T corresponding to X _line (T) = X _target (t), then the target vehicle 5 is assigned to the channel "i" if: $$Y_{\mathit{line}1}\left(T\right)<Y_{\mathit{target}}\left(t\right)<Y_{\mathit{line\; i}+1}\left(T\right)$$

The central computer 27 calculates a channel number i to be assigned to the carrier vehicle 3 according to the same principle, for example, the carrier vehicle 3 is assigned to the "i" channel if: $$Y_{\mathit{line\; i}}\left(t\right)<0<Y_{\mathit{line\; i}+1}\left(t\right)$$

It is thus determined whether the target vehicle 5 is either on the same track as the carrier vehicle 3, or on an adjacent track (a track deviating from the track of the carrier vehicle 3) to that of the carrier vehicle 3 or on a track located more than one lane away from the track of the carrier vehicle 3.

The central computer 27 is configured to send an activation signal to the means 25.

The means 25 for signaling the presence of the follower vehicle 5 comprises, for example, a driver's seat vibration mechanism or an indicator on the dashboard or the side mirror which is triggered when the activation signal is received from the central computer. 27.

The central computer 27 is further configured to determine whether the presence of a follower vehicle 5 in the SAM zone has been reported by the computer 35. The central computer 27 is further configured to compute a time before collision (in English, Time To Collision ') TTC using longitudinal relative distance and longitudinal relative velocity provided by calculator 35.

The central computer 27 is configured to send an activation signal when a follower vehicle 5 is in the 'Dead Angle Surveillance' (SAM) area, or when a follower vehicle is not in the SAM area, but on a track adjacent to that of the carrier vehicle 3 and has a collision time TTC (in English, 'Time To Collision ') less than a predetermined TTC threshold, for example, 4 seconds.

The operation of the system 15 according to the first embodiment of the present invention will now be described.

The trajectory (X, Y) followed by the carrier vehicle 3 of the system 15 in the reference frame of the carrier vehicle 3 is determined according to equations (1) to (5) using measured values of the speed V _x of the carrier vehicle 3 and the yaw rate V _psi of the carrier vehicle 3.

A position of the lane marking lines on the road at each instant pos _{Y line} (T) for T between 0 and t with respect to the vehicle 3, and along the axis y of the vehicle 3 at the instant T, is determined by using a front camera CA1 and / or a rear camera CA2.

A trajectory (X _line (T), Y _line (T)) of each of the lane marking lines with respect to the vehicle 3 is calculated using the values of the trajectory (X (T), Y (T)) taken by the vehicle and the position of the lane marking lines according to equations (6) to (7).

A _target position X (t), Y _target (t) of a follower vehicle 5 (or more follower vehicles) relative to the carrier vehicle 3 is determined using the values measured by the radar system 34 of the relative distance and the relative angle of the target vehicle with respect to the carrier vehicle.

A channel number i is assigned to a target vehicle 5. For each target vehicle, the calculated trajectories (X _line (T), Y _line (T)) and the relative position of the target vehicle (X _target (t), Y _target (t)) are used to assign a channel number i to the target vehicle 5.

The time T corresponding to X _line (T) = X _target (t) is found and then the target vehicle 5 is assigned to the channel "i" if: $$Y_{\mathit{line\; i}}\left(T\right)<Y_{\mathit{target}}\left(t\right)<Y_{\mathit{line\; i}+1}\left(T\right)$$

The carrier vehicle 3 is assigned to the "i" channel if: $$Y_{\mathit{line\; i}}\left(t\right)<0<Y_{\mathit{line\; i}+1}\left(t\right)$$

It is determined whether the target vehicle 5 is on a track adjacent to that of the carrier vehicle 3 and an activation signal is sent to the means 25 when the target vehicle 5 is in the 'Dead Angle Surveillance' (SAM) area, or when the target vehicle 5 is on an adjacent lane and is not in the SAM zone, but has a collision time TTC lower than a predetermined TTC threshold.

The Figure 6 illustrates the case where the carrier vehicle of the lane-assisting system according to the present invention changes lanes from the third lane V3 to the second lane V2. The target vehicle 5 which is on the second track V2 is no longer on the adjacent track 9 calculated by the system according to the present invention and is no longer reported to the driver of the carrier vehicle 3. A target vehicle 13 which is on the third channel V3 (or the first channel V1) will be signaled because it is in the adjacent channel 9 calculated by the system according to the present invention.

The Figure 7 represents a lane-assisting system 150 according to a second embodiment of the present invention.

The system 150 comprises means 19 for determining a position of a follower vehicle 5 with respect to the vehicle 3, means 25 for signaling the presence of a follower vehicle 5, a central computer 38 and a navigation and positioning system. satellite 40.

The means 19 for determining a position of a follower vehicle 5 with respect to the vehicle 3 and the means 25 for signaling the presence of a follower vehicle 5 in a track adjacent to the vehicle track 3 are identical to the means 19 and the means 25 of the first embodiment.

The satellite navigation and positioning system (such as a GPS navigation system) has an accuracy of at least 1 meter and includes storage means 41 (such as a flash memory), a computer 42 and a computer. receiver 43 signals emitted by a constellation of satellites, for example, GPS signals.

The receiver 43 includes a microprocessor for simultaneously processing the signals received from the satellites and for calculating the position (X _abs (t), Y _abs (t)) of the vehicle 3 in the "land" reference system in order to determine the trajectory followed by the vehicle 3 carrier of the system 150 in the "Earth" reference system. The position (X _abs (t), Y _abs (t)) is supplied to the storage means 41 and recorded.

The storage means 41 include a mapping of the roads of the road network in the "Earth" reference system and software for operating the system.

The mapping of the road network tracks in the "Earth" reference system makes it possible to know the trajectory of the tracks in the "Earth" reference system.

The computer 42 is configured to determine, from the road network mapping data, the trajectories of the lines delimiting the channels (X _{line abs} , Y _{line abs} ) in the "Earth" reference system of each of the line marking lines. The calculated trajectories are stored in the storage means 41.

où ψ(t) est l'angle de lacet.The calculator 42 is able to calculate an angular position of the vehicle (yaw angle) relative to the "Earth" marker by using the evolution of the position (X _abs (t), Y _abs (t)) provided by the receiver 43 of the carrier vehicle, for example, by using two successive positions (stored in the storage means 41) at times t and t + dt, according to the following equation: $$\mathit{\psi }\left(t\right)=\arctan \left(\frac{Y_{\mathit{abs}}\left(t+\mathit{dt}\right)-Y_{\mathit{abs}}\left(t\right)}{X_{\mathit{abs}}\left(t+\mathit{dt}\right)-X_{\mathit{abs}}\left(t\right)}\right)$$

where ψ (t) is the yaw angle.

The satellite navigation and positioning system 40 thus makes it possible to determine, in the "Earth" reference system, the trajectories of the lines delimiting the channels, as well as the position (X _abs (t), Y _abs (t)) and the position angular of the carrier vehicle 3.

The central computer 38 of the system 150 is connected to the means 19, the means 25 to signal the presence of the follower vehicle and to the satellite navigation and positioning system 40.

The central computer 38 includes storage means 137, such as a flash memory, including software for operating the lane-assist system 150.

The central computer 38 is able to receive the trajectory (X _abs (t), Y _abs (t)) followed by the carrier vehicle of the satellite navigation and positioning system 40 as well as the trajectories of the lines delimiting the channels (X _{line abs} , Y _{line abs} ) in the "earth" reference of each of the channel marking lines calculated by the computer 42.

The central computer 38 is furthermore capable of receiving the relative position X _target (t), Y _target (t) of a follower vehicle in the reference of the carrier vehicle and the signal indicating the presence of a follower vehicle in the SAM zone the computer 35 as well as the values of the relative distance, the relative angle of a follower vehicle and the longitudinal relative speed. The central computer 38 determines that the follower vehicle 5 is not in the SAM zone when the signal indicating the presence of a follower vehicle in the SAM zone is not received and the central computer 27 receives the relative position X _target ( t), Y _target (t) of the computer 35,

$$Y_{\mathit{cible\; abs}}\left(t\right)=\left(Y_{\mathit{cible}}\left(t\right)+Y_{\mathit{abs}}\left(t\right)\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)+\left(X_{\mathit{cible}}\left(t\right)+X_{\mathit{abs}}\left(t\right)\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)$$

The central computer 38 is further configured to implement an algorithm (stored in the storage means 137) in order to calculate the positioning of the target vehicle (s) in the "Earth" reference, using the position (X _abs (t), Y _abs (t)) and the angular position of the vehicle 3, according to the following equations: $$X_{\mathit{target\; abs}}\left(t\right)=\left(X_{\mathit{target}}\left(t\right)+X_{\mathit{abs}}\left(t\right)\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)+\left(Y_{\mathit{target}}\left(t\right)+Y_{\mathit{abs}}\left(t\right)\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)$$

$$Y_{\mathit{target\; abs}}\left(t\right)=\left(Y_{\mathit{target}}\left(t\right)+Y_{\mathit{abs}}\left(t\right)\right)\times \cos \left(\mathit{\psi }\left(t\right)\right)+\left(X_{\mathit{target}}\left(t\right)+X_{\mathit{abs}}\left(t\right)\right)\times \sin \left(\mathit{\psi }\left(t\right)\right)$$

The central computer 38 is configured to implement an algorithm (stored in the storage means 137) to identify the target vehicle (s) needing to warn the driver of the carrier vehicle.

The central computer 38, using the algorithm, calculates a channel number i to be assigned to a target vehicle 5. For each target vehicle, the calculated trajectories (X _{line abs} , Y _{line abs} ) and the relative position of the vehicle target (X _{target abs} (t), Y _{target abs} (t)) are used to assign a channel number i to target vehicle 5.

From the knowledge, in the Earth reference system, of the positioning of the lines delimiting the channels, the positioning of the target, and the positioning of the carrier vehicle, a channel number is assigned at time t to the carrier vehicle 3, as well as to the target vehicle 5.

It is thus determined whether the target vehicle 5 is either on the same track as the carrier vehicle 3, or on an adjacent track (a track deviating from the track of the carrier vehicle 3) to that of the carrier vehicle 3 or on a track located more than one lane away from the track of the carrier vehicle 3.

The central computer 38 is configured to send an activation signal to the means 25.

The central computer 38 is further configured to determine whether the presence of a follower vehicle 5 in the SAM zone has been reported by the computer 35. The central computer 38 is further configured to compute a time before collision (in English, Time To Collision ') TTC using longitudinal relative distance and longitudinal relative velocity provided by calculator 35.

The central computer 38 is configured to send an activation signal when a follower vehicle 5 is in the 'Dead Angle Surveillance' (SAM) area, or when a follower vehicle is not in the SAM area but on a track. adjacent to that of the carrier vehicle 3 and has a collision time TTC (in English, ' Time To Collision ') less than a predetermined TTC threshold, for example, 4 seconds.

The operation of the system 150 according to the second embodiment of the present invention will now be described.

The trajectory (X _abs (t), Y _abs (t)) followed by the carrier vehicle 3 of the system 150 in the "Earth" reference frame, the angular position of the carrier vehicle 3 and the trajectories of the lines delimiting the tracks (X _{line abs} , Y _{line abs} ) in the "Earth" frame of each of the lane marking lines are determined and supplied by the system 40.

A relative position X _target (t), Y _target (t) of a follower vehicle 5 (or more follower vehicles) relative to the carrier vehicle 3 is determined using the values measured by the radar system 34 of the relative distance and the relative angle of the target vehicle with respect to the carrier vehicle.

A positioning (X _{target abs} (t), Y _{target abs} (t)) of the target vehicle (s) in the "Earth" coordinate system is calculated using the position (X _abs (t), Y _abs (t)) and the angular position of the vehicle 3, according to equations (11) and (12).

By knowing, in the "Earth" reference system, the positioning of the lines delimiting the channels, the positioning of the target, and the positioning of the carrier vehicle, a channel number is assigned at the instant t to the carrier vehicle 3, as well as than the target vehicle 5.

It is determined whether the target vehicle 5 is on a path adjacent to that of the carrier vehicle 3 and an activation signal is sent to the means 25 when the target vehicle 5 is in the SAM zone, or when the target vehicle 5 is on a adjacent lane and is not in the SAM zone, but has a collision time before TTC lower than a predetermined TTC threshold.

It will be understood that various modifications and / or improvements obvious to those skilled in the art can be made to the various embodiments of the invention described in the present description without departing from the scope of the invention defined by the appended claims. For example, the central computer 38 may comprise the system 40.

Claims (10)

1. A lane change assistance system (15; 150) for a vehicle (3) including:

   - means (17; 40) for determining a path taken by the carrier vehicle (3) on a road;

   - means (19) for determining a position of a following vehicle (5) with respect to the carrier vehicle (3);

   - means (27; 38) for determining if the following vehicle (5) is situated in an adjacent lane to the lane of the carrier vehicle (3);

   characterized in that it comprises

   - means (23; 40) for determining a path of the lane marking lines on the road; and

   - means (25) for signalling the presence of the following vehicle (5) in the adjacent lane after a change of lane of the carrier vehicle (3).
2. The system (15) according to Claim 1, characterized in that it further includes means (21) for determining, as a function of time, a position of the lane marking lines with respect to the vehicle (3).
3. The system (15) according to Claim 2, characterized in that the means (23) for determining a path of each of the lane marking lines are configured to calculate a path of each of the lane marking lines using the path taken by the vehicle (3) and the position of the lane marking lines.
4. The system (15; 150) according to any one of Claims 1 to 3, characterized in that it is configured for determining the path of a following vehicle (5) using the paths of the lane marking lines and the position of the following vehicle (5) with respect to the vehicle (3), and for determining the path of the vehicle (3) using the paths of the lane marking lines and the position of the vehicle (3).
5. The system (15) according to any one of the preceding claims, characterized in that the means (23) for determining a position of the lane marking lines with respect to the vehicle (3) include a camera positioned at the front of the vehicle and/or a camera positioned at the rear of the vehicle.
6. The system (150) according to Claim 1, characterized in that it includes a system of navigation and of positioning by satellite (40) including a mapping of the lanes on the road, the system (40) being configured for determining a path of the lane marking lines on the road from the mapping of the lanes.
7. A method for determining the presence of a following vehicle (5) in a lane adjacent to a lane of a carrier vehicle (3), characterized in that it includes steps which consist of:

   - determining a path taken by the carrier vehicle (3) on a road;

   - determining a path of the lane marking lines on the road;

   - determining a position of a following vehicle (5) with respect to the carrier vehicle (3);

   - determining if the following vehicle (5) is situated in a lane adjacent to the lane of the carrier vehicle (3); and

   - signalling the presence of the following vehicle (5) in the adjacent lane after a change of lane of the carrier vehicle (3).
8. The method according to the preceding claim, characterized in that it further includes the step which consists of:

   - determining, as a function of time, a position of the lane marking lines with respect to the vehicle (3).
9. The method according to the preceding claim, characterized in that during the step of determining a path of the lane marking lines, a path of each of the lane marking lines is calculated by using the path taken by the vehicle (3) and the position of the lane marking lines.
10. A motor vehicle including the system (15; 150) according to any one of Claims 1 to 6.

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